@BeforeEach
  void setUp() throws Exception {
    try {
      // prevents access problems with a just previously closed port
      Thread.sleep(50);
      lnk = new KNXNetworkLinkFT12(Util.getSerialPort(), TPSettings.TP1);
    } catch (final Exception e) {
      Util.tearDownLogging();
      throw e;
    }
    nll = new NLListenerImpl();
    lnk.addLinkListener(nll);

    frame =
        new CEMILData(
            CEMILData.MC_LDATA_REQ,
            new IndividualAddress(0),
            new GroupAddress(0, 0, 1),
            new byte[] {0, (byte) (0x80 | 1)},
            Priority.LOW);
    frame2 =
        new CEMILData(
            CEMILData.MC_LDATA_REQ,
            new IndividualAddress(0),
            new GroupAddress(0, 0, 1),
            new byte[] {0, (byte) (0x80 | 0)},
            Priority.URGENT,
            true,
            3);
    frame3 =
        new CEMILData(
            CEMILData.MC_LDATA_REQ,
            new IndividualAddress(0),
            new GroupAddress(0, 0, 3),
            new byte[] {0, (byte) (0x80 | 0)},
            Priority.NORMAL);
  }
 /**
  * Test method for {@link
  * KNXNetworkLinkFT12#addLinkListener(tuwien.auto.calimero.link.NetworkLinkListener)}.
  */
 @Test
 public final void testAddLinkListener() {
   lnk.addLinkListener(nll);
   lnk.addLinkListener(nll);
 }